N, K = map(int, input().split())
if N == K * (K + 1):
    print(K + 1)
    for i in range(N):
        for j in range(N):
            if i == j:
                print(".", end="")
            else:
                print("#", end="")
        print()
    exit()


d, m = divmod(N, K * K)
r = 0
while True:
    if r * r >= m:
        break
    r += 1

size = K * d + r
res = [[0] * size for _ in range(size)]
p = 0
for _ in range(d):
    for i in range(K):
        for j in range(K):
            res[p + i][p + j] = N
            N = max(0, N-1)
    p += K

for i in range(r):
    for j in range(r):
        res[p + i][p + j] = N
        N = max(0, N-1)

print(size)
for r in res:
    for i in r:
        if i:
            print("#", end="")
        else:
            print(".", end="")
    print()